How to choose reducer lubricating oil suitable for different ambient temperatures

The core of selecting reducer lubricating oil is to determine the ISO VG viscosity grade according to the ambient temperature and operating temperature rise, match the oil type and additives, and follow the manufacturer's manual; low temperature gives priority to fluidity and low pour point, high temperature gives priority to oil film stability and oxidation resistance, and heavy load/impact requires an extreme pressure (EP) formula.

1. Temperature range and viscosity speed matching (ISO VG, mainly industrial gear oil)

2. Oil type and additive selection

Normal working conditions (indoor, medium load, 10℃~40℃): Priority is given to CLP/LCKD extreme pressure industrial gear oil. Mineral oil is sufficient and has high cost performance.

Low temperature/large temperature difference (≤-10℃ or significant temperature difference between winter and summer): Choose PAO/ester synthetic gear oil with high viscosity index, low pour point, smooth start and stop, and stable oil film.

High temperature/long-term continuous operation (≥40℃ or box temperature rise ≥80℃): Use high-temperature anti-oxidation and anti-coking synthetic oil or high-grade mineral oil to inhibit oxidative deterioration and sludge formation.

Heavy load/impact/pitting risk: Must contain EP (extreme pressure) additives, and use anti-micropitting formula if necessary to prevent gluing and pitting corrosion.

Worm gear (copper alloy worm gear): Avoid extreme pressure agents containing active sulfur, and choose special worm gear oil or mild EP formula to prevent copper corrosion; synthetic worm gear oil can be used for high temperature and heavy loads.

Food/medicine/clean environment: Choose NSF H1 and other food-grade certified oils, which are non-toxic, low-volatile, and degradable to avoid pollution.

3. Key Selection steps and precautions

Check the manual first: use the viscosity and oil type recommended by the manufacturer as the benchmark, and then fine-tune according to the actual ambient temperature; SEW and other brands often recommend 220, 320 for heavy duty/high temperature, and 150 for low temperature.

Check the actual temperature rise: ambient temperature + operating temperature rise = box oil temperature. If the oil temperature is ≥80℃, it should be treated as high temperature working condition. If necessary, install a cooler or replace with higher viscosity/synthetic oil.

Consider both speed and load: lower the viscosity by one gear at high speed and light load to cool down and save energy; raise the viscosity by one gear at low speed and heavy load to thicken the oil film; select high viscosity index synthetic oil for contradictory working conditions (high speed + heavy load).

Control the oil change cycle: low temperature/high temperature/dust/water vapor environment shortens the cycle; synthetic oil can usually extend the oil change cycle, but it needs to be determined according to actual working conditions and oil test results.

Grease scenario: For vertical, small, sealed, maintenance-free or difficult-to-fill reducers, select semi-fluid grease (No. 00/0) and match it according to the grease’s operating temperature range; use synthetic grease for low temperatures ≤ -20°C, and use high-temperature grease for high temperatures ≥ 100°C.